Working 4 Cylinder Air Engine Model

thingiverse

11/10/19 -I had to repost this because it got flagged for associating a brand name with it. I'm working on better-designed inline 2 and 4 parts, which will be posted when they're ready. Edit as of 4-16-19: -I revised the cam ends to make them shorter so the 50mm bolts fit deeper. -I revised the flywheel hub to have a collar that prevents the bearing from pushing down on it. -I added crank spacers to keep the connecting rods centered. -I increased the diameter of the piston slightly, making it easier to sand for a better fit in the cylinder and reducing scratchiness. -I shortened the crank gear by 1mm to allow for tolerance with the crank in the block. This is a small 4-cylinder air engine I designed and built using 3D printed parts and store-bought bolts and springs. Assembly instructions are available for purchase, guiding you through each step. To see more about this engine and a video of it running, check out my Instagram page @CompressedCreations. I apologize for the parts not being oriented correctly to print when they're uploaded to a slicer, but simply rotating them will allow them to print. I used 3D Printer OS to slice all my files and included specs in the instructions. Some basic knowledge is necessary; I refer to components by their names, and if you don't know general engine terms, it may be difficult to understand. For example, "sand the cylinder walls to match the piston." It's not extremely complex but isn't for someone with no engine knowledge. Engine Specs: - Approximately 1000 RPM at 1psi (lung pressure) - Maximum RPM is unknown but likely around 5000 - Displacement: 21.5 CC's - Bore: 19mm - Stroke: 19mm Required tools for assembly: -Sandpaper, 200+ grit (I recommend closer to 400) -1.5mm allen wrench -Small phillips screwdriver -Razor blade (Xacto knife recommended) -Small amount of epoxy/super glue Parts Required: -M2x16mm bolt (10) -M2x50mm bolt (2) -1mm rod ~25mm (4) -3mm rod ~18mm (4) -M2x22mm bolt (4) -M4x15mm spring (4) -M2x12mm bolt (8) -M2 nut (14) -6mm airsoft bb (4) -8mmx2mm O-ring (4) -5x11x4mm bearing (4) -.25" brass tube (1") This engine is a fun desk toy but was designed with the intention of also powering things. I integrated an axle connection in the flywheel so it can power objects, and you can print your own replacement flywheel and attach it to the universal hub. The engine doesn't require the flywheel to run, so it can be removed if desired. It also doesn't need the engine stand; however, it's optional but nice for displaying the engine. The hub has four 1.8mm holes in an 8x8mm square to accept M2 bolts. If you want to create something like a propeller or any other kind of drive component, design the object with this bolt pattern and attach it to the crank output on either side of the engine. It produces decent torque at just 1psi (lung pressure) but is very strong when connected to an air compressor. However, an issue with using an air compressor is that it may not be able to supply the volume of air this engine can take so 30psi from the compressor might drop to 3psi by the time it reaches the engine. If you build this, please send me a video or link to it! I'd also love to see it run at extremely high pressures to see what it can handle. I hope you enjoy this model and please contact me with any problems or questions at elismith427@gmail.com.